The present invention relates generally to processing of wastes, and the recovery and recycling of certain metals. More particularly, the present invention is directed to a transformer dismantling and salvaging system wherein heavy duty power transformers are mechanically demolished so that the constituent metals can be recovered for subsequent recycling.
Heavy duty industrial and utility power transformers of the Three kilovolt- ampere and 500 and above kilovolt-ampere range are in widespread use. Such transformers have, on the average, a useful life expectancy of between five to fifteen years, depending upon a variety of factors. Transformers subjected to light use which have been erected in well shielded areas, for example, may survive for upwards of twenty years. Their less fortunate counterparts, exposed to lightening hits or mechanical damage from wind or tornadoes may be removed from service in a much shorter time. In any event the vast quantities of used and no longer useful transformers accumulating across the country present a difficult solid waste problem.
It is known in the salvage business to demolish or strip used power transformers to recover their metal constituents. A variety of problems exist in such work however, and there are a number of dangers as well. Many transformers produced up until the 1970's were filled with transformer oil containing dangerous polychlorinated biphenyl (PCB) compounds. While PCB transformer oil is no longer used in new transformers, it still can be found in older transformers which are subject to recycling. Moreover, almost all power transformers are filled with some type of oil, and current EPA regulations establish strict guidelines for the disposal of such oils.
From a transformer salvaging standpoint, the important thing is to properly capture and contain the oil for subsequent transfer to appropriate specialists for disposal. The problem of capturing transformer oil is extremely aggravating, since the stripped transformers are heavy, cumbersome and difficult to maneuver by laborers. Since, at present, the recycling work is done manually, an opportunity for exposure to such chemicals exists.
It is known in the salvage business that transformer cores are of value. The laminated steel material may be recycled, and if disposal has been done properly, the entire core may be reused, substantially as is. If the core is obsolete or is otherwise damaged, it may end up as scrap metal for subsequent resmelting. Likewise, the metal windings of the transformer are valuable. At present transformers are manually taken apart with hammers, saws, and the other hand tools. The copper or aluminum windings are then manually removed from the transformer debris. The recovered windings are incinerated to remove the paper, varnish or other coverings, and then the recovered metal is resmelted. Of course it is recognized that the resmelting of recovered metal is more efficient than the processing of new raw ores.
Power transformers of the type contemplated herein involve shell type transformers and core-form transformers. The shell type of transformer consists of two cores both of which are penetrated by one band of windings. In other words the primary winding and the various secondaries are all wound in a single band which extends between the centers of the mutually coupled, adjacent cores. Modern high power transformers are of the core-form type. These consist of one heavy magnetic core, which includes a pair of windings disposed about its opposite legs. The primary advantage of a core form transformer is that the mean length turn of the windings is reduced.
Hence core form transformers are more efficient and generate less heat. However, in the past they have been more difficult to manufacture, and when worn out, they have been more difficult to disassemble. In any event it is necessary to consider modifications to hardware to accomplish the processing of all types of high power transformers in a viable recovery system.